Decoding RNA Editing Sites Through Transcriptome Analysis in Rice Under Alkaline Stress.

Area of Science:

• Plant Molecular Biology
• Genomics
• Stress Physiology

Background:

• Ribonucleic acid editing (RE) is a crucial post-transcriptional modification influencing gene expression.
• RNA editing sites (RES) in rice, particularly under alkaline stress, remain underexplored.
• Alkaline stress significantly impacts rice yield, necessitating research into plant adaptation mechanisms.

Purpose of the Study:

• To investigate the impact of alkaline stress on RNA editing sites (RES) in rice chloroplast and mitochondrial genomes.
• To characterize the nature of RNA editing events and their effect on amino acid changes.
• To explore the expression patterns of key RNA editing factor genes under stress.

Main Methods:

• Prediction of RNA editing sites across the entire mRNA of rice chloroplast and mitochondria.
• Analysis of editing efficiency, types of editing events (A-G, C-T, G-A, T-C), and codon changes.
• Gene Ontology analysis to identify biological functions of edited genes.
• Quantitative analysis of pentatricopeptide repeat (PPR) and organelle zinc-finger (OZ1) gene expression.

Main Results:

• 3336 RNA editing sites (345 in chloroplast, 2991 in mitochondria) were predicted with an average efficiency of ~55%.
• Most editing events resulted in non-synonymous codon changes, primarily altering amino acids towards a hydrophobic trend.
• RNA editing efficiency increased under alkaline stress, with upregulation of PPR and OZ1 genes observed.
• 88 genes showed stress-induced amino acid changes through RNA editing, suggesting a role in adaptation.

Conclusions:

• RNA editing is upregulated in rice under alkaline stress, contributing to adaptation by modifying amino acid sequences.
• The study provides a foundation for identifying RES in other crops and developing alkaline-tolerant rice varieties.
• Upregulation of PPR and OZ1 genes highlights their importance in mediating RNA editing under stress conditions.